The electrospray mass spectrometer was examined in an effort to increase its sensitivity and maximize the fragmentation of peptides and proteins. Multiple charges, while important in causing fragmentation, do not appear to work via their repulsive energy as shown by a small molecule maximizing these effects as well as a series of specially designed quaternary salts. The electrospray spectrum of water clusters has been examined and clusters containing greater than 200 water molecules have been prepared with either hydronium or ammonium ions both of which were found to exhibit magic numbers at n=21 and 28 molecules. The structure of the other water aggregates of high mass was found to be consistent with the formation of ice (Ic) rather than the common ice (Ih). These cluster analyses have been also found to exist with formamide, a compound having many physical properties similar to water. A series of lipids isolated from brain has been found to be related to the diacylgalactosyl diglycerides through mass spectrometry and NMR. Their function in brain is understood at present. The common histidine tag used for recombinant DNA production of proteins for NMR and x-ray analysis has been found to be retained in one case even after extensive purification and its presence detected by electrospray mass spectrometry under carefully controlled conditions. Under routine conditions of acidic spray, the spectrometer reports the expected mass, so that mass spectrometry alone does not provide assurance that nickel is not attached.